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AD5754R DAC ISsue with STM32F3xx

Question asked by franck.eudaric@arturia.com on Jan 20, 2015
Latest reply on Sep 2, 2015 by wentworth

I'm using an STM32F302 to pilot DAC AD5724R by SPI.

I'm also using the EVAL -AD5754REBZ.

The STM32F3xx SPI2 is 16-bit frame. So no other way as my source is a 32-bit word I send 32 clocks and 2x16-bits (endian mode).

As far I understand the AD5754R needs exactly 24 clocks. So instead of using the DAC A voltage output I used the SDO serial output pin to get my voltage as Datasheet said:

Jumpers configuration is as followed:

 

Reference

Jumper

Function

LK1

A

REFIN chosen

LK2

Close

This link connects the VOUTA output of the AD5754R to the VIN0 input of the on-board ADC (AD7323):  When inserted, the voltage at the VOUTA pin can be read back to the PC.  When removed, the voltage at the VOUTA pin is disconnected from the on-board ADC input.

LK3

Close

This link connects the VOUTB output of the AD5754R to the VIN1 input of the on-board ADC (AD7323):  When inserted, the voltage at the VOUTB pin can be read back to the PC.  When removed, the voltage at the VOUTB pin is disconnected from the on-board ADC input.

LK4

Close

This link connects the VOUTC output of the AD5754R to the VIN2 input of the on-board ADC (AD7323):  When inserted, the voltage at the VOUTC pin can be read back to the PC. When removed, the voltage at the VOUTC pin is disconnected from the on-board ADC input.

LK5

Close

This link connects the VOUTD output of the AD5754R to the VIN3 input of the on-board ADC (AD7323):  When inserted, the voltage at the VOUTD pin can be read back to the PC. When removed, the voltage at the VOUTD pin is disconnected from the on-board ADC input.

LK6

A

USB port selected as the 5 V digital circuitry power supply source.

LK7

B

Position B selects the evaluation board to be controlled by the external source J8.

LK8

B

This link selects the digital supply voltage value for the AD5754R and the on-board ADC (AD7323): +3.3V  chosen.

LK9

B

This link selects the negative supply voltage:

Position B selects the AVSS connection of J9 as the negative supply voltage (bipolar operation).

LK10

Open

This link connects the voltage reference input of the on-board ADC to the selected voltage reference source.

LK11

Open

LDAC pin is pulled to DVCC through a 10 kΩ resistor. LDAC

LK12

Open

CLR pin is pulled to DVCC through a 10 kΩ resistor. CLR

LK13

Open

This link sets the state of the BIN/pin (LK7 must be in Position B): the BIN/pin is pulled to DVCC through a 10 kΩ resistor.

I first send the output range for DAC A to be +/- 5V sending 0x00080003.

Then I power up DAC A sending 0x00100001

Then I send my data 0x0000FFFF and then 0x00000000.

I expected a square waveform moving from +5V to -5V

Here what I've got!!!

Yellow: MOSI / Green: Clock/  Pink: CS=SYNCn / Violet: SDO

I don't understand where is my mistake as there should be one!

Many thanks for your help.

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